The present invention relates to a crushing tip used for an eye surgery using ultrasonic vibrations, and especially, relates to the crushing tip which crushes, sucks, and discharges a crystalline lens in the eye surgery for treating a cataract and the like.
For example, as for a method for operating the crystalline lens of an eye of a patient who has the cataract, recently, phacoemulsification and aspiration (PEA) is becoming widespread. In this operation, a crushing tip attached to a horn of an ultrasonic handpiece which generates ultrasonic vibrations is prepared, and the crushing tip is inserted into the crystalline lens to provide the ultrasonic vibrations, so that the crystalline lens is crushed and emulsified by the crushing tip, and after the emulsified crystalline lens is sucked and taken out by the crushing tip, a replacement artificial lens (intraocular lens) is implanted in a capsule of crystalline lens wherein an inside becomes empty so as to perform a vision correction (for example, see Japanese Unexamined Patent Application Publication No. 2009-95662 (see paragraph [0002]); WIPO Publication No. WO2013/125056 (see paragraph [0004]); US Patent Application Publication No. US2009/0099536A1; Japanese Patent No. 4800802; and Japanese Patent No. 4473192).
Incidentally, as for such a crushing tip, in order to enhance a crushing efficiency of the crystalline lens by a torsional mode (repetition rotational mode), there is used a crushing tip wherein a tip portion is curved (for example, see paragraph [0002] of Japanese Unexamined Patent Application Publication No. 2009-95662).
However, the crushing tip wherein the tip is curved as mentioned above has a disadvantage of easily generating a cavitation which has a possibility of causing a negative effect to an iris or an endothelial cell by swinging vibrations of the tip of the crushing tip (for example, see paragraph [0004] of WIPO Publication No. WO2013/125056). Also, since a center of gravity is located outside the tip, at a time of the torsional mode, a “shaft shift” occurs so as to increase an invasion into an incised wound, thereby there is a possibility of generating an “incised wound insufficiency”. Moreover, since a current cataract surgery has a small incision, most cataract surgeries are performed “without a suture”, however, if a large aggression is applied to the incised wound, self-closing does not occur, thereby having a problem of increasing burden on an operator and a patient. Moreover, in the crushing tip wherein the tip is curved, the tip faces downward, so that the tip of the crushing tip contacts a posterior capsule so as to have a possibility of a posterior capsule rupture as well.
In view of the aforementioned problems, recently, a crushing tip with a straight type wherein a whole crushing tip has a straight shape has become popular, however, in such a straight-type crushing tip, a problem is how the crystalline lens can be efficiently crushed and emulsified, and there are proposed various tips for enhancing a crushing and emulsifying efficiency while restraining the cavitation from occurring (see WIPO Publication No. WO2013/125056; US Patent Application Publication No. US2009/0099536A1; Japanese Patent No. 4800802; and Japanese Patent No. 4473192).
However, even in the crushing tips described in the aforementioned Patent Publications, there is a problem that the crushing and emulsifying efficiency is still insufficient.
The present invention is made in view of the aforementioned problem, and an object of the present invention is to provide a crushing tip which can largely improve the crushing and emulsifying efficiency relative to the conventional crushing tips, and especially, the crushing tip which can enhance the crushing and emulsifying efficiency while effectively restraining the cavitation from occurring.
Further objects and advantages of the invention will be apparent from the following description of the invention.